EPA published an approach modeled partially after the compartment-based priority setting approach described in the December 28,1998, Federal Register Notice [PDF, 28pp., 228KB, About PDF] in which EPA provided details about, and requested comment on, its EDSP (63 FR 71542). EPA's approach for selecting the initial 50 to 100 chemicals for Tier 1 Screening, Chemical Selection Approach for Initial Screening in an FR Notice [PDF file, 17pp., 125KB, About PDF] focuses on human exposure-related factors rather than on a combination of exposure- and effects-related factors. Although EPA's approach focuses on chemicals with relatively greater potential human exposure, EPA believes that the approach also captures many chemicals with widespread environmental exposures to other organisms.

This list should not be construed as a list of known or likely endocrine disruptors. Nothing in the approach for generating the initial list provides a basis to infer that any of the chemicals selected interfere with or are suspected to interfere with the endocrine systems of humans or other species.

Determining the consequences to the organism of the activities observed
in Tier 1, and

Establishing the relationship between doses of an endocrine-active
substance administered in the test and the effects observed.

The Tier 2 tests are longer in duration than Tier 1 tests and are designed
to encompass critical life stages and processes as well as a broad range
of doses, and are intended to be administrated by a relevant route of
exposure. These tests will enable EPA to obtain a more comprehensive profile
of the biological consequences of a chemical exposure and identify the
dose or exposure that caused the consequences. Effects associated with
endocrine disruption may not be expressed until later in the test subject's
life, or may not appear until the reproductive period is reached. Therefore,
Tier 2 tests usually encompass two generations and include effects on
fertility and mating, embryonic development, sensitive neonatal growth
and development, and transformation from the juvenile life stage to sexual
maturity.

Tier 1 Screening and Tier 2 Testing data collected as part of EDSP will
help EPA to identify and characterize hazard (the potential to cause harm).
When EPA integrates and interprets all of the endocrine disruptor-related
hazard data in consideration with other available hazard information,
EPA performs a hazard assessment. EPA will then conduct an exposure assessment
by looking at the amount of chemical to which wildlife or humans are likely
to be exposed. The final step in the process is the risk assessment, through
which EPA integrates the information about the potential harm of a chemical
with the likelihood that someone or something will be exposed. Based on
scientifically sound risk assessment the Agency can make risk management
decisions regulating the chemical(s). For more information about how EPA
conducts health risk assessments, read EPA's Office of Pesticide Programs'
fact sheet entitled, "Assessing
Health Risks from Pesticides".

You will need the free Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more. If you need help accessing these PDF documents, please contact William Wooge at 202-564-8476 or wooge.william@epa.gov for assistance.